Patent GB-442821-A (GB)
Title: Method of welding and welding machine
IPC: B23K11/00
Filed: 1935-05-22
Abstract: 442,821. Welding cylinders &c. FORD MOTOR CO., Ltd., 88, Regent Street, London.-(Ford Motor Co. ; Rouge Plant, Dearborn, Michigan, U.S.A.) May 22, 1935, No. 14950. [Classes 83 (ii) and 83 (iv)] In a process of producing line welds a number of spot welds are made in succession spaced along the line of the weld so as to secure two parts together at a number of points, and further series of spot welds are made, the individual spots of each series overlapping the spots of the preceeding series until the line has been completed. As applied to the welding of sheet metal jackets 28, Fig. 1, to an engine cylinder block 27, a machine comprises a U- shaped frame 29 carrying guide rods 19 for a work support 18. The engine block 27 rests on inclined rollers 14 on the support and is held down by rollers 16 on a bracket 17 attached to the upper part of the frame 29. Arcuate clamping dogs 21 on the support 18 hold the block in an endwise direction and are provided with teeth engaging racks on hydraulic plungers 20. The support is moved by the piston of a hydraulic cylinder 25. The jackets 28 are welded at each side along three seams A, B, C, two sets of electrodes 34 being provided on the frame at each side for the seams A, B, and a set of electrodes 60 being pivoted at each side of the bracket 17 for the seams C. The electrodes 34 are actuated directly by hydraulic plungers 32 and levers 56 carrying the electrodes 60 are oscillated by plungers 59, springs 35 being provided for withdrawing all the plungers. Each row of electrodes A .. C extends along substantially the length of the block 27 and consists of twelve electrodes, the first six of each of the rows A, B being connected by flexible leads 54 to a transformer 26, and the first six of the rows C being connected by leads 58 to another transformer 26, there being thus six transformers in all for seventy-two electrodes. Oil or other liquid is contained in a sump 47 in the machine frame and is supplied to rotary valves 37 at a pressure of two hundred pounds per square inch by a high pressure pump 41, Fig. 2. One valve 37 is provided for each row of electrodes and has a series of radial ports 38 arranged along a helix so that one port will communicate with each electrode plunger during a revolution and cause each electrode in a row to be pressed against the work in sequence After such a sequence of spot welds, which is effected in all the rows simultaneously, the work is advanced slightly by the hydraulic cylinder 25 and a second series of welds, overlapping the first, is effected. This procedure is repeated until the entire spaces between the original welds have been filled up. The six valves 37 are rotated in unison. Cooling electrodes. The plungers 32, Fig. 2, for the electrodes in the rows A, B have axial passages 42, 43, communicating respectively with the pressure chambers 31 and the exhaust sump 47 and providing a flow of cooling oil to the electrodes 34 during operation of the plungers. The cross-sectional area of the passages 42, 43 is small compared with that of the ports 38 so that escape of oil to the sump will not materially affect operation of the plungers. When the plungers are not operating, oil at a pressure of fifty pounds per square inch is supplied to the passages 42, 43 for cooling the electrodes, by means of a low pressure pump 50, reservoir 48 and non-return valve 52, an oil cooler 53 being provided in the circuit. The electrodes 60 are also cooled.